1. Field of the Invention
The invention relates to wireless communication, and in particular to a transmit/receive switch and a radio frequency integrated circuit (RFIC) for use in wireless communication.
2. Description of the Related Art
In half-duplex communication systems, either the transmitter or receiver would be ON at any given time. Such systems generally adopt one single antenna and a transmit/receive switch, wherein the switch performs the selection of transmitting or receiving paths.
Communication systems support wireless and wired communications between specific communication devices. Such communication systems range from national and/or international cellular telephone systems, the Internet, to point-to-point in-home wireless networks. Each type of communication system is constructed, and hence operates, in accordance with one or more communication standards. For instance, wireless communication systems may operate in accordance with one or more standards including, but not limited to, IEEE 802.11, Bluetooth, advanced mobile phone services (AMPS), digital AMPS, global system for mobile communications (GSM), code division multiple access (CDMA), local multi-point distribution systems (LMDS), multi-channel-multi-point distribution systems (MMDS), and/or variations thereof.
For each wireless communication device to participate in wireless communications, a radio transceiver (i.e., receiver and transmitter) is built-in or coupled to an associated radio transceiver (e.g., a station for in-home and/or in-building wireless communication networks, RF modem, etc.). In many radio frequency (RF) transceivers, the receiver and transmitter operate in a half duplex mode and thus share the antenna. To facilitate the sharing of the antenna, the RF transceiver includes a transmit/receive (T/R) switch, which is off-chip from the transmit and receive sections.
U.S. Pat. No. 7,092,679 discloses a transmit/receive switch comprising an impedance matching circuit that provides minimal impedance to minimize incoming and outgoing signal loss. However, since the impedance matching circuit connects to both the transmitter and receiver, and since the transmitter and the receiver typically employ transistor devices of different thickness and power supply level, the transmit/receive switch presents reliability issues when high voltage swing is coupled to transistor devices with thin oxide, resulting in oxide breakdown and circuit failure.
Thus a need exists for a transmit/receive switch with improved circuit reliability.